Thermoelectric generator with air-cooling heat recovery device from wastewater

A lot of waste water has not been recovered in China. The waste water emissions also cause thermal pollution and damage to the ecological environment. This paper presents a waste heat recovery solution based on thermoelectric power generation technology. The general structure of an air-cooling heat recovery device is designed. The physical model is established and solved. The temperature changing law along the flow direction is obtained. The effects of main factors such as thermoelectric module geometry, heat sink geometry and wastewater flow rate are analyzed. The results show that the heat sink design is the most key factor affecting the performance of air-cooling thermoelectric power generation device. The wastewater temperature decreased 0.19 °C per meter in the flow direction with a 120 mm wide square pipe. The area power density of the thermoelectric module is about 0.30 kW/m2 and the efficiency is about 1.28%. The cost recovery period of the equipment is about 8 years. The main reason for the uneconomical is the low temperature of the wastewater.